1. Field of the Invention
This invention relates to a disc cartridge for housing a disc-shaped recording medium, such as an optical disc or a magneto-optical disc, loaded on a recording and/or reproducing apparatus.
2. Description of the Related Art
There has hitherto been used a disc cartridge housing an optical disc, a magneto-optical disc or a magnetic disc and which is loaded therewith on a recording and/or reproducing apparatus.
As this type of the disc cartridge, there is known such a device described in the U.S. Pat. No. 4,510,546.
With the disc cartridge described in these publications, a disc as a information recording medium is rotationally housed within a main cartridge body unit which is rectangular in shape. The main cartridge body unit has a recording and/or reproducing opening for allowing a portion of the housed disc to be exposed to outside across the inner and outer rims of the disc. This main cartridge body unit carries a shutter member, rectangular in cross-section, adapted to be moved along the front side of the main cartridge body unit for opening/closing the recording and/or reproducing opening. This shutter member is moved parallel to the one side at a center portion of the main cartridge body unit along the front surface of the main cartridge body unit to open/close the recording and/or reproducing opening, so that, at the corner portions of the rectangular main cartridge body unit, there are formed regions not covered by the shutter member and not faced by the magnetic disc. Thus, in these regions, there are provided cartridge supporting portions engaged or supported by the positioning pins provided on the recording and/or reproducing apparatus when the disc cartridge is loaded on the recording and/or reproducing apparatus.
As a disc cartridge housing a disc as an information recording medium, there is known such a one as described in the U.S. Pat. No. 4,614,990.
In the disc cartridge described in this Publication, a disc is rotatably housed in a rectangular main cartridge body unit. The main cartridge body unit is provided with a recording and/or reproducing opening for exposing part of the magnetic disc housed therein to outside across the inner and outer rims of the disc. The disc cartridge is provided with a recording and/or reproducing opening larger in size than the main cartridge body unit.
As a disc cartridge housing a disc as an information recording medium, there is known such one as disclosed in the U.S. Pat. No. 5,570,252. The disc cartridge disclosed in this Publication has an opening in a lateral surface of the main cartridge body unit. The magnetic head is introduced via this opening into the inside of the disc cartridge into sliding contact with the signal recording region of the magnetic disc. In this disc cartridge, the shutter member adapted for opening/closing the opening is mounted for performing movement along a lateral side of the main cartridge body unit.
Meanwhile, with the disc cartridge disclosed in the U.S. Pat. No. 4,510,546, in which the shutter member is moved in parallel along the front surface of the main cartridge body unit to open/close the recording and/or reproducing opening, it is difficult to provide a cartridge supporting portion sized sufficient to support the disc cartridge in stability on both sides of the front surface of the moving main cartridge body unit, such that it is difficult to load the disc cartridge on the recording and/or reproducing apparatus in stability.
Also, the disc cartridge as disclosed in the U.S. Pat. No. 4,614,990 is provided with a recording and/or reproducing opening larger in size than the main cartridge body unit, the shutter member for opening/closing the recording and/or reproducing opening is also increased in size, and moreover is mounted on the front side of the main cartridge body unit so that the shutter member will be moved from the center portion of the main cartridge body unit to the vicinity of the lateral sides of the main cartridge body unit. Therefore, a cartridge supporting portion engaged or supported by the positioning pins provided on the recording and/or reproducing apparatus cannot be provided on a corner of the front surface along which is moved the shutter member of the main cartridge body unit to render it difficult to load the disc cartridge on the recording and/or reproducing apparatus in stability.
Moreover, the disc cartridge disclosed in the U.S. Pat. No. 5,570,252, the magnetic head is inserted into the inside of the main cartridge body unit via a narrow opening formed in the lateral surface of the main cartridge body unit, there are imposed limitations on the recording and/or reproducing mechanism that can be used. This disc cartridge is extremely difficult to apply for accommodating an optical disc used in conjunction with an optical pickup device. Also, the shutter member is adapted for opening/closing an opening narrow in width and longer than it is wide, and hence it is narrow and elongated in profile to render it difficult to realize a stable movement.